1. Field Of The Invention
The present invention relates to fixtures for mounting high intensity lamps and, more particularly, to an adjustable fixture allowing control of beam spread for the light output of a high intensity discharge lamp.
2. Description Of The Prior Art
Spotlights and flood lights are often utilized to light the exterior of buildings and monuments to highlight certain features and create an aestheticly appealing image to an observer. In some uses a broad light beam is desired to illuminate a large surface area, while in other uses a narrow light beam to highlight a particular area or feature of an object to be illuminated is more desirable. In the prior art one specific fixture with a predetermined light focusing pattern is typically used for lighting a broad area and a separate fixture with a different focusing pattern is used for lighting a smaller area for accent and emphasis especially with respect to monuments and sculptural objects. Typical of prior art fixtures is one shown in U.S. Pat. No. 4,410,933, issued Oct. 18, 1983 to Blake et al and assigned to the present assignee. The Blake et al patent shows a luminaire having an indicator and positive stop to allow adjustment and setting of the angle of aim of the fixture relative to the object being illuminated but allowing only one focusing pattern. Thus, the prior art requires use of multiple fixtures where multiple focusing patterns are required.